As part of its year 2000 goals, the National Cancer Institute has recommended that Americans lower significantly their consumption of dietary fat. High fat diets are associated with increased risk of many cancers, most importantly colon, rectum, prostate and possibly breast. Little is known about the best means to promote large scale dietary change and, because fats are central in usual American cuisine, successful intervention will provide considerable challenge. The primary goals of this project are to develop measures of of attitudes, beliefs, and behavior related to selection of lower fat diets. The ability to define and measure clearly the important determinants of selecting diets low in fat will contribute to an orderly and scientific approach to the design and evaluation of public health dietary interventions. Two groups of participats will be recruited: 1) 25 women for a pilot phase involving a cultural anthropological semistructured interview on diet behavior and health beliefs, and testing of preliminary study instruments; 2) 100 women for two cycles of a diet-habit interview by telephone, a four-day diet record, and completion of a set of standardized instruments to measure diet behavior, beliefs, and attitudes. Participants will be selected based on their usual dietary fat intake, divided into similar-sized low- and high-fat groups (less than 33$% and greater than 38% calories as fat, respectively). Outcomes will be: 1) a set of scales which measure reliably dietary behavior related to the maintenance of low-fat diets, and 2) a set of measures for factors which, based on the existing literature and the results of in-depth interviews, may motivate the selection of foods lower in fat. In addition, the data collected will allow the development and testing of behavior-based, short, dietary screens. Preliminary investigation of factors motivating selection of low-fat diets will also be possible, by contrasting food selection motives between persons selecting low- and high-fat diets.